docs: def on_linecolor(self, *args):
          """If I don't yet have the instructions for drawing the selection box
          in my canvas, put them there. In any case, set the
          :class:`Color` instruction to match my current ``linecolor``.
  
          """
          if hasattr(self, 'color'):
              self.color.rgba = self.linecolor
              return
  
          def upd_box_translate(*args):
              self.box_translate.xy = self.pos
  
          def upd_box_points(*args):
              self.box.points = [0, 0, self.width, 0, self.width, self.height, 0, self.height, 0, 0]
  
          self.boxgrp = boxgrp = InstructionGroup()
          self.color = Color(*self.linecolor)
          self.box_translate = Translate(*self.pos)
          boxgrp.add(PushMatrix())
          boxgrp.add(self.box_translate)
          boxgrp.add(self.color)
          self.box = Line()
          upd_box_points()
          self.bind(
              size=upd_box_points,
              pos=upd_box_translate
          )
          boxgrp.add(self.box)
          boxgrp.add(Color(1., 1., 1.))
          boxgrp.add(PopMatrix())